Fig. 4: Condensins I and II constrain nucleosomes in mitotic chromosomes.
a Diagram of condensins I and II, which share the same SMC ATPase subunits (SMC2 and SMC4) and have distinct sets of non-SMC regulatory proteins (CAP-H, -D2, and -G for condensin I, and CAP-H2, -D3, and -G2 for condensin II). b Fluorescent images of FA-fixed HCT116 cells depleted (KD) of SMC2 (condensins I and II). Top, control HCT116 cells (DMSO vehicle only). Bottom, SMC2-mClover depleted HCT116 cells with IAA treatment. From left to right, DNA (DAPI), SMC2-mClover, and merged. c Box plots with dots of the SMC2-mClover signal intensity. A.U. means arbitrary unit. Whiskers, bounds of box and gray bars show maxima, minima, first/third quantiles, and median values. Median values of control and SMC2 KD are 1.6 × 103 (n = 13 cells) and 1.5 × 102 (n = 10 cells), respectively. ***P < 0.0001 (P = 1.7 × 10−6) by Wilcoxon rank sum test (two-sided). d MSD plot (±SD among cells) of TMR-labeled interphase (Interphase, gray, n = 13 cells) and metaphase nucleosomes (Metaphase, black, n = 13 cells) in living HCT116 cells without or with condensins I and II depletion (SMC2 KD, magenta, n = 10 cells) from 0.05 to 0.5 s. The Kolmogorov-Smirnov test (two-sided) was used to determine P values. ***, P ≤ 0.0005, for with versus without SMC2 KD (P = 1.3 × 10−4), not significant (N.S.) for interphase versus metaphase with condensins KD (P = 0.44). MSD exponents from Supplementary Fig. 3c and AC values from Supplementary Fig. 3d are also shown in brackets.
